Method of casting metal ingots and apparatus therefor



Feb. 1, 1944. l T SCULLY ET AL f 2,340,493l

METHOD 0F CASTING METAL INGOTS AND APPARATUS THEREFOR Filed May 4', 1942 by the ingot is temperature of the grade of Y steel cast, and

Ygots to remain in the .nace will be provided with Patented Feb. Vl, 1944 mamon or cosmo monarca John '.r.

METAL INGOTS TBEBEFOR Lawrence,` N. Y., and George H.

Wyckoff, Mountain Lak es, N. J.

Application my 4, im, serial No. 441,682 27 claim. (ci. zz-s'z) 'I'he present invention relates to the art oi.'

I casting ingots and has especial reference to a method and apparatus for casting lngots of steel or alloys of steel for later rolling or other mechanical working.` l l Amongl the general objects of the invention is a method of casting ingots whereformed with a thick side skin; the provision of amethod of casting an ingot which will have a thick skin of substantially uniform thickness for a major portion of its length; the provision of a method for providing an ingot with a relatively deep zone, r of fine grain to e provision of presenta strong surface or near surface zone for mechanical working, for

example such as rolling; to reduce cavities, blow holes and the like; and to generally improve the soundnessof ingots.

'A further object is the provision proved method of castingingots which are to be charged hot into soaking pits or reheating furnaces, for bringing the ingots to uniform and proper rolling temperature, which will provide zar. zone of fine Brain for considerable'radial depth by virtue of side wall cooling'by the mold and which will provide compensation, or partial compensation, for the loss of ingot heat by side wall cooling by supplying, while the the molds, heat at relatively high temperature, or temperatures, as the case may be, to the lower portion of the mold, heat which is of relatively high temperature to and below the solidiilcation steel or alloy of in suitable volume, reduce the length of time required for such inpitr or reheating furnace to reach the lmiform and proper temperature preparatory to rolling.

is the provision of an whereby ingots which are to be a. soaking pit or reheating furf a thick skin of fine grain for considerable inward or radial depth of substantially uniform thickness for the Ina-jor porttliloen' of their lengths and in which heat loss to be considerably retarded by supplying externally generated heat at relatively high temperature and suitable volume to the lower portion of the mold, and thereby reduce the length of time required for such-ingots toNremain in the soaking pit or reheating furnace to reach the uniform and proper temperature preparatory to rolling. A still further object is the provision of a method'whereby ingots which have been provided with A `still further object' improved method charged hot'into ingots are in a thick skin by prolongedconductivity of heat in side wall'cooling will be spaced from the inner side wall of the mold at or near stripping timeand thereby facilitate complete stripping by the crane.

A still further object is the provision ofa meth- I od of casting ingots in big-end-down moldshavthicker walls continue to bottom of the mold from the ingot will 'section in which of the poured molten formed between skin end-down molds ing inset-forming chambers of tapering crossthe vertical mold body is forced against the skin molten and causes the molten interior tosbe squeezed upwardly.

A further important object is the provision of a method whereby ingots cast in big-end-down molds having ingot-forming chambersI of tapering cross-section will be side wall cooled in the early stage of the casting substantially uniformly inwardly and the normal length of time of contact between the insot skin and mold .wall will be increased by a relative body movement therebetween,- and in the later stage will be cooled progressively upwardly.

Further objects are the provision of apparatus, in which the method may be carried out, which is simply constructed, inexpensive, durable. easily assembled and manipulated; which will provide efllcient control of the Operation; will facilitate stripping of ingots with a minimum risk of damage to their skins.

Other objects will hereinafter appear-. During casting of steel ingots the side surfaces mass are cooled relatively quickly by the side walls of the mold and a skin is formed which gradually grows in thickness as more and more heat is absorbed by the side walls of the mold and whichv in cooling tends to shrink away from the side walls of the mold. As the process of solidiiication progresses the growing skin or `shell -builds up into thickerwalls surrounding a diminishing grow toward the center. As the skin or outside of the ingot becomes solid metal and the hotter interior continues to cool and contract, the skin shrinks away from ttrl side wallsof the mold and becomes spaced t erefrom by an air gang-the loss of contact with the mold wall stops the direct conductivity of heat from the solidifying mass and the result is slower cooling and enlargement in crystal growth. Also. by the manner of solidiilcation combined with natural physical laws certain defects are producedl in ingots such `as or pipe, or blowholes and pipe. The air gap and mold side wall in bigor shell while the interior isl and which molten interior and the segregation, top cavities.

having tapering inset-forming l rigidly supported at ,a squeeze upwardly of the molten possible after pouring `ing furnace which at best y 'suitable level below erably, butnot necessarily so, rate sufficient to chambers is relatively large due to the fform of the molds and the direction of ingot shrinkage and settling relative to the direction of increased width of mold chamber, the gap being further.

tion of the length of'the ingot it is a4 desirable.

advantage in subsequent' mechanical working. Further, if in a big-end-down mold suiliclent force be exerted on the mold body so that the tapering chamber wall will cause the skin or shell of the solidifying ingot to be moved laterally inwardly while the interior of the ingot is still molten, preferably for considerable depth, and is its base, the result will be interior which however slight will reduce the depth of top cavities or pipes, or in the case of molds equipped with hot tops will reduce the amount of molten metal required in the hot top to feed'downwardly.

Steel ingots which are intended to hot in soaking pits or reheating furnace to have their temperature equalized or brought to uniformity throughout preparatory to rolling are in common practice, considered by large producers as best practice, stripped from the molds as soon in order that they may be charged in the soaking pits before much of their original heat is'lost uniform and propenrolling temperature quickly and also keeping low the fuel cost of theA reheatis economically lneillcient` and expensive. The time at which it is practicable to strip ingots varies under well known conditions. it being customary for reasons above cited to strip a great percentage of ingots while their interiors are still molten and to allow many ingots, such as those of high carbon content vand alloy steels to remain in their molds n- -til their interiors have become completely solidifled. and, as is well known. the solidiflc'ation range of different steels varies wldelv. the difference being so much as 800. or approximately as rmuch, for high carbon steels containing more than, 005 per cent carbon, the solidlflcation temperature for these ranges in Fahrenheit from approximately 2100 to approximately 1300": while forv low carbon steels the solidification temperature ranges from 2550 F. to approximately 1650 F. Also, as is well known, for many steels the desired rolling temperature is very high, for example, soft steel at about 2200 F. and spring steel at about 2`000 F. i

Our present invention may be carried out in any suitable mold.. In carrying out the invention we prefer to use a metallic big-end-down mold, and to pour molten metal into the chamber to a the top of the mold at a prefproduce a relatively rapid'rise of molten metal in the chamber cooling by the mold poured mass horizontally or of the upper portion of the radially opposite the i metallic side walls of the chamber occurs relatively quickly,y after commcncementof; side wall cooling of the lower portion of the poured mass and wherebyinward radial cooling of the poured whereby initial peripheral side wall greater radial depth,

moved in sliding contact with theingot skin and mass for its heighth in contact with the metallic side walls of the mold progresses at a substantially uniform radial rate and continuing the side cooling at a preferred rate to produce a' skin of substantially uniform thickness so that the skin a plane parallel, or substantially parallel, to the chamber face of the mold side walls. To increase the length of time which the ingot skin would normally be in contact with the side walls of the mold and lengthen the time 0f relatively fast freezing and thereby thicken the skin or shell of the ingot by the formation of small crystals to a the vertical mold body is during the sliding contact the side wall cooling is continued at a preferred rate tp thicken the skin be charged l thereby being brought to the l ment or elements,

substantially uniformly inwardly for the length or heighth of the skin between the molten interior and' the chamber walls. Preferably, the downward progression of the mold body is extremely slow, at least in its early stage, relative to the ingot skin shrinkage and its settling down the downward while the in the mold, and, again preferably, movement of the mold is under way Lshell of the ingot is relatively compressible or is vsuiilciently compressible to be laterally moved inwardly by the mold that the plane of the outer surface of the skin major-*portion of its heighth with the inner face of the side walls of the mold. During at least some of the time the ingot shell is relagvely compressible or movable inwardly by the mold body we prefer toremove or diminish the support 'for the mold body at a rate which will give support to the mold body during its downward progression to prevent a sudden drop. In some instances after the formation of a suitably thick skin or shell by -slow sliding contact, and while the shell is relatively movable inwardly by the mold body and the interior is still molten, we prefer to withdraw the support mold body to effect a relatively quick inward movement of the ingot shell so that the width of the container, so to speak, of the fluid portion is narrowed and the molten interior forced upwardly. Preferably, to improve the squeezing eect of the mold body on the ingot shell suitable force is employed to urge the mold body downwardly.

body so on the skin of the ingot to continue its downward progression-as contraction of the ingot or expansion of the mold permits. Any suitable mutable support may be used to support the mold body longitudinally movable relatively to the bottomclosure of the ingot-forming chamber, or any suitable combination of elements; we prefer to use a support susceptible to combustion, composed of any suitable element or combination of elements such as wood of any suitable degree of hardness or softness, in laminated assembly or otherwise, or lin combination with another ele,-

or coke, or coal, or a mixture of sand and a combustible binder. The use of a combustible support to mutably support the mold body, as pointed out in our application for patent which ls issuingl as Patent No. 2,281,718, on May 5, 1942, supplies during burning heat in the lower portion of the mold and retards dissipation of i wm tend to shrink to will be parallel for the rom the mold body to cause the .v of the 'supiilliv assists in to accelerate the burning,

tion of the ingot of relatively greaterheat .site the Wall contacting last to rise than the cooling power'of the Walls portion of;y theingot shell relatively movable" or compressible irifthls region for at least a part of theljtime the e'of the shellmay be forced to'- wards the a'xi the mass.- In the present ln vention we pre to exercise control over the rate Vof combustionfof-the combustible supportfand vary its rate Zoff-Icombustion, later stage of the downward mold body by increasing the preferably in the progression of the rate of combustion therefore the withdrawal, of' the support of the mold body to 'effect a squeeze of the-molten interior and at the same ascuas while' the 4oi' the maintaining Vthe lower time increase the temperature of the heat supplied to the lower portion of the mold, and in someinstances if desired, we may use a combusticombinationwith any elements. When using a combustible support capable of evolving great heat and when varying the temperature of the `lheat, for example by increasing it for above cited purposes and or for the purpose of retarding the cooling of the lower portion of ingots intended to vbe charged hot into soaking pits or a reheating furnace, heat of relatively high temperature to the solidiiication temperature of the particular grade of steel or alloy of steel may be .produced l but low enough relativelythereto and` relatively to the solidiiication temperature or temperatures of aiected mold parts as not to cause fusion of' the casting,l or deformation or fusion of the mold;

'In someginstances especially incasting steel or alloys of steel subject to the formation of relatively deep cavities or pipe at the upper end of the ingot we may prefer afterthe formation preferably of a substantially uniform skin to lthe `desired radial depth, to alter the side wall of radial-cooling rate of theA upper portion "of the metallic mold walls by retarding thedissipation of heat therefrom while the interior of at least the upper poris still molten, and preferably by retarding the dissipation of heat at a progressively increasing ratupwardly, and thereby cool or solidify, as the may be, the upper portion of the ingot ho zb tally opposite the merogressively upwardly. eeming the molten mass into a mold having side -iiallsof substantially uniform heat absorbing power or having side walls absorbing power oppolevels of molten mass "'walls to the ingot-forming chamber, and pouring the molten metal into the chamber at a temperaturesuiliciently high above the freezing point of the molten metal'relative to the relationshipof the cross-sectionalv thickness of the side walls of the mold to the cross-section of the ingot-forming chamber so that heat absorbed by the mold walls from the poured mass will heat the outer metallic periphery of the upper portion of the mold interior of at least theupper portion poured mass is still molten radially opposite the upper portion of the inner metallic periphery of the ingot-forming chamber; andthen. after the formation of the desired skin thickness, altering the predetermined cooling rate of the side progressively upwardly, the heat conductive rate of the upper portion of the side walls Iby retarding dissipation of absorbed. heat from the surface4 of the outer periphery of the metallic mold body opposite the ingot contacting surface and storing, so to speak, the absorbed` heat in the walls to delay dissipation of'heat 'from' the solidifying ingot. This may be accomplished in any suitable manner and by any suitable means known in the art.

We prefer to accomplish this byapplying externally to the mold walls a conservator of heat ,surrounding the outer periphery of the vertical mold body andadapted to retard dissipation of heat from the upper portion ofthe mold, and

` which. includes a circumferentially extending in the present invention,

/desirable instances,

body of low heat conducting power encased in a durable frame, and'a compressible elastic material of low heat conducting power, such as asbestos,l to serve as a resiliently yieldable heat-insulating'facing `to peripherally engage, or substantially peripherallyI engage the outer 'surface of the vertical mold body.

In carrying out the invention with ingots of large section or generally large size, or in casting such or ingots of the various grades of steel, or in the casting of ingots-generally, especially in big-end-down molds, it may .be desirable in many instances to supply a relatively large volume of heat to the lower portion of the mold, particularly to the support for .the ingot base, and in also, in which for reason of loss of heat in the length of time of side wall contact ofthe mold with the ingot skin, the time required for a particular ingot to remain in the soaking pit orreheating furnace, that is an ingot charged'hot therein, in preparation for rolling,` maylfbe reduced, relatively,. by considerably retardi ingot, for example a combustible material such as coke,v and regulating a. supply of compressed p solidiiication of the air under suitable pressure, heat of relatively high temperature may be produced to considerably retard'the dissipation of heat from the bottom and lower portion of the ingot at any desired stage: in casting steels of high solidiilcation temperatures, this supplied fheat of relatively high temperature will in most instances 'be considerably below, as afgeneral practice, the temperature of casting steels of low solidication temperatures, the temperature of suppliedv heat willlbe closer to the solidification temperature of the metal being cast. g f Referring to the drawing: j, Figure 1 is a vertical sectional view of an ingot mold assembly with parts of the apparatus shown in section and parts in elevation,

Figure 2 is a vertical sectional view of a modifcation of ingot` mold assembly withparts of the section and parts shown in mold by virtue of increased ng theloss of'heat from its lower portion or bottom. By burning a combustible material capable ofevolv-r ing great heat under the base support of the metal being cast, while in shape with rounded corners and termediate the corners laterally project the plug-like botto able quantity of combustible material, preferably rounding the plug-like ous material, sistency of heavy bottom-closure.

view of the ingot mold assembly shown'in Fig. 2 equipped with 'a hot top.

Figure 4 is a fragmentaryl vertical sectional view.

bf amodification of parts. u

' Referring to -the drawing` in more detail: In Fig. 1, on a suitable primary support 5, suchas afloor, platform or transfer car, a generally rectangular metallic stool l, preferably of cast iron, is supported on legs y tom of the stool is spaced from the primary support. Centrally in the stool a relatively large recess 1 is provided of generally rectangular into which ina plurality of spaced tooth-like projections 8 which are integral parts of the metal of the stool and have 4their upper faces rigidlysupport a removable rectangular metallic plug-like bottom-closure III with rounded corners and which is preferably provided with a continuous laterally projecting ledge 9, integral therewith, and preferably of cast iron. The bottom-closure on its upper side is preferably provided with a relatively deep and wide recess surrounded by a rim of metal'edecreasing in'Kcrosssection` towards the top. Inthe recess 1 below -closure is provided a suitin the form of coke, which is capable of as shown, in suitable sizes, evolving great heat.. Surbottomfclosu're is a continuous channel, rounded or curving at the 1corners, and in the channel is a mutable support I2 supporting a vertical mold body I3 which upon withdrawal or diminution of the mutablesupport will descend downwardly'into the channel and downwardly relatively tb the rigidly supported plug-like ,bottom-closure. AThe mutable support may belof anyk suitable material, and is preferably of combustible material, and may be of any suitable combustible material for example coal or coke in any suitable form or suitable wood or woods. In soine instances the combustible support may consist of suitable lengths of wood accommodatable in the straight portions of the channel and at the rounded corners pieces of wood of small section may be stood on their ends and stacked in groups at the cor' ners. Sealing material preferably of argillacesuch as nre clay, having the contar is applied on the inner side of the upper face of the combustible support and the guter side of the upper end of the rim of the Enough argillaceous material is provided so that the vertical mold body as it is positioned will squeeze it or bulge it so that it will extend fromthe rim of the plug to the'inner periphery of the mold at the bottom and prevent the formation of a tin on the ingot. The Avertical mold body is a big-end-down mold having the cross-sectional thickness of the wall moderately diminishing upwardly and is of rectangular shape with rounded corners externally and internally. The inner peripheral wall I4Y of the body tapers, preferably moderately, inwardly in the upward direction, is preferably smooth, and may be coate if desired, with any suitable material or was 'I pension of the mold walls. In some instances we intermediate which the bot-v sizes, or any' known in the art. The heighth of e the combustible support is such as to provide the peripheral side,

in the same plane and erably longitudinally and the sides of the stool.

' a plurality of passages prefer,"without increase of mass of mold, to superimpose on the mold, preferably u pon its outer a body of great weight which will act as a force to urge the mold body downwardly orl at a desired stage will force the mold body downwardly, and in the,early stages of the casting the body of great weight may be removably supported independently of the mold and later its weight caused to bear onthe mold. As shown herein the outer vertical mold body is provided witha plurality of laterally projecting tooth-like portions upon which is suspended 'a circumferentially continuous (ring-like) symmetrically balanced body of great weight I5 preferably provided witha facing I6 of heat-insulating material spaced from the peripheral side of the mold a suitable distance and which is wide enough in opposite portions to permit lowering of the body past lifting lugs commonly a part of ingot molds. In the stool below the combustible material II is a chamber I1 from which a vertical passage extends to the bottom of the stool and in the vertical passage is a forcibly tted pipe of the stool. From the chamber extend a suitabie'number of suitably arranged passages lIt communicating with the recess in which the combustible material II is positioned to distribute air to the combustible material. Extending outwardly from the channel through the sides of the stool are a plurality ofpassages I9, prefvertically spaced on l Also communicating with the channel from the outer sides of the stool are 20 shown in dotted lines, of suitable number andl arrangement, in series. Provided in the. stool, also, are two L-shaped passages 2I Vandl 2Ia extending horizontally as elbowed pipeseach having one longitudinal end closed and the other end communicating with the outer sides of the stool, preferably laterally of the corners, the latterends being obliquely or diagonally opposite each other and beingprovided with forcibly fitted short pipes having their outwardly from the sides of the stool. At suitably spaced distances from each other and laterally oiset to the passages 20 are a series of passages communicating with the channel from the L-shaped passages 2l Communicating with the recess 1, in locations laterally of the toothlike projections 8 are a series of passages 22. In

some instances we provide means to close or for practical purposesto temporarily close, from the atmosphere the outer ends of the passages I9, 20 and 22 by removable covers 23 suspended upon the stool, along each fiat side thereof, and which can be easily removed at any desired period of the casting, and also, in some instances we may place argill'aceous material between the 'bottom of the outer periphery of the mold and the stool wall at the outer side and upper end of the channel. The removable covers will serve principally to prevent, other factors being considered, such metal as may be tapped in a supermolten state from causing too early reduction of the combustible support 'relative to initial skin formation by the heat absorbing power of the mold.. Connected to the externally threaded projecting ends of the pipe passages 2| and 2Ia respectively are, internally threaded couplings on peripheralside of the having an externally, threaded outer end projecting from the bottom I material the valve 3| and poured at usual "moving the coversl 23 Vorigination e:4v combustion may, if desired, be

nature of the combustible support. Preferably the combustion of the supair supply to the combustible support, :and the valve 29 provides controlof compressed air supply to the combustible material, coke as shown, in the recess 1, the valve 3| being normally open.` In'instances in which it maybe desirable to jointly control the supply oi' compressed both the combustible support and combustible will serve, valves 28 and 29 then being normally open; or in instances in which it may be desirable to jointly control the supply of compressed -air to the combustible support and combustible material in a plurality of molds the valve 32 will serve, the others being open in that event. In assembling .the mold parts the plug-like bottom-closure is positioned on the tooth-like supports 8 after the broken size coke is placed-in the recess. The outer periphery of the plug provides the inner side wall of the channel which is 'preferably of unii'onn width. 'I'he ledge may erate with .the stool to center the plug or the width of the mutable support in block-form may do so, and when for any desirable reasonl the4 periphery of the plug, purposes, is relatively side of the recess such argillaceous material. rate is such aswill provide a relatively rapid rise for insertionor removal widely spaced from the space may be iilled with mencement of pour especially so in casting large ingots, particularly' those long and wide or at slow rates to avoid splash or for other reasons. The construction shown in this figure of the vertical mold body is such that the thickness v upwardly proportionally to the. decreasel upwardly of chamber section, and in some in-. stances, particularly with long. wide chambers, the mold wall, may with advantage, decrease in thickness relatively less in relation to decrease of chamber section. The molten metal is poured to a heighth in the chamber which will provide a distance from the top of the mold to the top oi! the poured mass which is preferably greater than the distance which will be traversed by the downward progression of the mold body. Heat from the poured mass is conducted preferably by both the plug and mold body to the mutable support to burn itand combustion is supported by reatA the desired time. The

predetermined by the air to The preferred pouring l oi mold wall decreases` f Y of drop of the mit the body ofagreat weight to force the mold body downwardly. Heat from the poured mass conducted by the plug will burn the combustible material, coke, and compressed air will be introlar casting.

In some instances steel or steels'may be cast in metallic molds having greater cooling power of mold wall in the upper portion relatively to'the 3 than the ccoiingpower or the lower side walls relatively to the cross-section of the lower portion of the chamber, such .a construe 'on being wherein the. thic heat-insulating material of very low heat-conductivity. and on the inner peripheral face of the frame ispreierablya facing of compressible elastic heat-insulating material, for example asbestos. The conservator is made of two parts bolted or mold at the desired stage to percross-section of the upper portion of the chambery 6. l 2,340,4os`

V the mold may be equipped with a hot-top as supported by the top of the mold being provided with projections 48 to rest on the end of the mold. As the mold moves downwardly in sliding contact with the skin of the ingot the hot top is left upon the poured mass. In some instances in casting long ingots compressible elastic or combustible material may be interposed between the end of the mold wall and the projections 48.

, In some instances after movement of sliding contact with the ingot skin of the vertical mold body stripping will be facilitated by lowering the ingot and the risk of skin damage such as tears avoided. In the modification of structure shown in Figure 4 the ledge 9 of the plug-like'bottomclosure is provided with a suitable number of laterally projecting portions 9a to co-operate with the walls of the recess to serve to position and guide the plug, the upper end of the wall opposite the projections being rounded to facilitate seating the plug, the projections preferably/extending into accommodating vertical shallow channels in the recess wall; the vertical channels extend to holes 49 in the lower part of the stooll 6a. Having their lower portion in the holes in a sliding nt and the outer sides of their upper portions in the vertical shallow channels are a plurality of strong metal supports 50 provided with laterally projecting teeth I at their upper ends supporting the plug and are supported at their bottom ends by removable wedges 52 extending beheath the stool which at their thickV ends are provided with obtusely projecting faces 53 on laterally projecting end portions 54 to facilitate their withdrawal by use of a sledge or other forcing tool. After sliding contact of mold with ingot skin and also the reduction of the coke, removal of the wedges will lower the plug and the ingot supported thereon spacing the ingot the desired distance from the side walls of the mold. As an additional modification and advantage the outer wall 55 of the channel will cooperate with the extreme marginal end of the mold body 13b which, while in other respects isfthe same as previously described, is' in this instance provided with an outer periphery whose extreme marginal ends have a surface 56 paralleling and cooperable with the channel wall 55 to guide the mold body in its downward progression, the wall 51. in the stool being rounded to facilitate positioning the mold in the assembly.' I

The invention is susceptible to variations of forms, proportions and details within the broad principle without departure from the spirit of the invention, and having described it in itspreferred form for purposes of illustration and not for limitation, we claim: V

1. A method of casting ingots'including pour' ing molten metal into a vertical metallic mold provided with an ingot-forming chamber oftapering cross-section the larger end of `which is down, at a rate sufdcient to produce a relatively` rapid rise oi molten metal in the chamber whereby initial peripheral sidewall cooling by the mold of the upper portion of the poured mass radially opposite the metallic side walls of the chamber occurs relatively quickly after commencement of sidewall cooling of the lower-portionpof the poured mass and whereby inward cooling of the poured mass forl its heighth in contact with the metallic side wallsA of the mold progresses at a substantially uniform radial rate. continuing the side wall cooling at a substantially uniform radial rate to form a skin of solidified metal 5 on the poured mass to confine the molten interior, and providing sliding contact between the skin of the forming-ingot and the side walls of the mold by moving the vertical mold body longitudinally downwardly relatively to the formingl0- ingot and the base support of said forming-ingot.

2. A method of casting ingots including pouring molten metal into a vertical metallic mold` provided with anv ingot-forming chamber of ta- 15 pering cross-section, the larger end of which isy down, absorbing heat basally from the poured mass and absorbing heat by the side walls of the mold at a substantially uniform radial rate to forma skin of solidied metal to confine the molten interior, providing sliding contact-between said skin and the side walls of the mold and laterally compressing the poured mass by moving the vertical mold body longitudinallyV downwardly relatively to the forming-ingot and the base support of said forming-ingot and in' the direction in which the ingot skin is longitudinally shrinking and settling down in the mold.`

3. A method of casting ingots including pouring molten metal into a vertical metallic mould provided with an ingot-forming chamber of tapering cross-section, the larger. end of which is down, absorbing heat basally, and cooling the v poured mass along the metallic side walls of the mold at a radial rate sufficient to produce a skin on the poured mass of substantially uniform thickness to confin'e the molten interior,` providing sliding contact between the side walls of the mold and the skin of the forming-ingot by moving the vertical mold body longitudinally 40 downwardly relatively to the forming-ingot and the base support of said forming-ingot. and retarding during at least part of the downward progression of said vertical mold body the cooling of the lower portionl of the ingot by supplying heat generated outside the ingot-forming chamber to the lower portion of the metallic mold.

4. A method of casting ingots including pouring molten metal into a vertical metallic mold provided with an ingot-forming chamber of up` wardly tapering cross-section, absorbing heat basally,A and cooling the poured mass along the side walls of the mold at a radial rate sufiicient to produce a skin on the poured mass of substantially uniform thickness to confine the molten interior, providing sliding contact between the side walls of the mold andthe skin of the forming-ingot by producing a relative .longitudi- 4nal body movement between the side walls of the mold on the one hand and the forming-ingot so )and its base support on the other hand, and retarding the cooling of the lower portion of the ingot by supplying heat of relatively high temperature and generated outside the ingot-forming chamber to the lowex` portion df the metallic mold and to the bottom of the metallic bottomclosure of said ingot-forming chamber.

5. In a method of casting an ingotl in an ingot mold assembly inc uding the combination of a vertically extending mold body provided with an ingot-forming chamber of upwardly tapering cross-section and a separable metallic bottom-closure mutably supported for relative longitudinal body movement of each other by a combustible support adapted to supply heat to the lower portion of the mold, the steps of pourcross-section in ing molten metal into the chamber, f' absorbing heat basally, and cooling the poured mass along the side walls of the mold at radial rate sufilcient to produce a skinon f I vlaf-'poured mass of substantially uniform thicknessst'o conilne the molten interior, thicke h yskin, by providing sliding contact bet the side walls of the mold andthe ingotl' Pyburning the combustible support and cing a relative lon- 'ween said side walls Y; andand the poured ,-c'losure on the other hand while at least f i 1pper portion of said poured mass is relatively -e?inpressible,'and varying the rate 'of com of the combustible support to quicken its y ution and to increase the temperature of the heat Isupplied to the lower 'mass and chamber b0 support.

6. A method of casting an ingot in a vertical I metallic mold provided with an ingot-forming flciently v.high'above the freezing point of the molten metal relative' tothe relationship of the cross-sectional-thickness ofthe side walls of the mold to the cross-section of the ingot-forming chamber so that heat absorbed by the mold walls from the poured mass will heat the outer metallic periphery of the upper portion ofthe mold and will heat up said mold walls throughout their said upper portion thereof suficiently tov have partially solidified the poured mass and to have greatly retarded the heat absorbing rate of said mold walls in said upper portion thereof while the' interior of at least the upper portion of the poured mass is still molten radially opposite the upper portion of the inner metallic periphery of the ingot-forming chamvportion ofthe mold by the combustion of said got-forming chamber so that heat absorbed by the mold walls from the poured mass will heat the outer metallic periphery of the upper portion of themold and will heat up said mold walls throughout their. cross-section in said upper portion thereof suillciently to have partially solidiiled the poured mass and to have greatlyretarded the heat absorbing rate of said mold walls in said upper portion thereof while the interior i solidincation of the upper portion of the poured mass radially opposite the upper portion of ythe met-allie side walls of the chamber by circumferentially retarding the dissipation of heat from the outer peripheral metallic surface of the side walls of the mold in the upper portion radially opposite the ingot-forming chamber by closely surrounding said uppen peripheral metallic sur-l face with a body of heat-insulating material separable of said mold. A

8. A method of casting an ingot in a vertical metallic mold. provided with an ingot-forming chamber of tapering cross-section, the larger end of which is dwn, and side walls having the same, or approximately the same, heat absorbling rate horizontally opposite the smaller portion of said chamber as the heat absorbing Irate horizontally Iopposite the lower and ber, providing' sliding contact between the skin y of the partially solidified mass and the side walls of the mold by moving the side walls of the mold longitudinally downwardly relatively to the poured mass and the base support of said poured mass, and retarding the solidiflcation of the upper portionof the poured mass radially opposite the upperportion of the metallic side walls of the chamber by circumferentially retardlng the dissipation of heat from the outer peripheral metallic surface of the side walls of themold .in the upper portion radially opposite the ingotforming chamber by closely surrounding said outer peripheral metallic surface with a body of heat-insulating material separable of said mold.

7. A method of casting an ingot in a .vertical metallic mold provided with an ingot-forming chamber of tapering cross-section, thle vlarger end of which is down, which includes pouring molten metal into the chamber at a rate to produce a relatively rapid rise of molten metal in the chamber whereby initial peripheral sidewall cooling by the mold of the upper portion of the poured mass radially opposite the metallic side walls of the chamber occurs relatively quickly after commencement of side wall cooling of the lower portion of. the poured mass and inward radial cooling of the poureed mass for its heighth in contact with the metallic sidewalls of the mold progresses at a substantially uniform ra-J" chamber of tapering cross-section,

larger portion oi' said chamber, which includes pouring molten metal into the chamberat a temperature sufilciently high above the freezing point "of the molten metal relative to the relationship of the cross-sectional thickness of the side walls of the mold to the cross-section of the ingotforming chamber so that heat absorbed by the mold walls from the poured mass will heat the outer metallic periphery of the upper portion of the mold and will heat up said mold walls throughout their cross-section in said upper portion thereof sumciently to have fled the poured mass and to have greatly retarded the heat absorbing rate of said mold walls in said upper portion thereof while the interior of at least the upper portion of the .poured mass is still molten radially opposite the upper portion forming chamber, providing sliding contact between the skin of the partially solidified mass and the side walls of the mold by moving the side walls of the mold longitudinally downwardly relatively to the poured mass and the base support of said poured mass, and progressively retarding upwardly the solidiilcation of the upper portion of the poured mass radially opposite the upper portion of the metallic side walls of the chamber by circumferentially retarding the dissipation of heat from the outer peripheral metallic surface of the side walls of the mold in the upper portion radially opposite the ingot-forming chamber.

9. A method of casting` an ingot in a vertical metallic mold provided with an ingot-i'orming the larger end of which is down, which includes pouring molten metal into the chamber at a rate to produce a relatively rapid rise of molten metal in the chamber whereby initial peripheral -sidewall cooling upper and partially solidi-l by the rmold of the upper portion of the poured' mass radially opposite the metallic sidewalls of the chamber occurs relatively quickly after commencement of side wall cooling of the lower portion of the poured mass and inward radial cooling of the poured mass for its height in contact with the metallic sidewalls `of the mold progresses at a substantially uniform radial rate for a period of time, and pouring said molten metal at a temperature sulilciently high above its freezing point relative to the relationship of the crosssectional thickness Vof the sidewalls of the mold to the cross-section of the ingot-forming chaml ber so that heat absorbed by the mold walls from the poured mass fwill heat the outer metallic periphery of the upper portion of the mold and will heat up said mold wallsfthroughout their cross-section in said upper portion sufilciently to have partially solidiiled the poured mass and to have greatly retarded the heat absorbing rate `and at least the upper portion o f its interior is still molten, retarding during at least part of the downward progression or the mold walls the cooling of the lower portion of the'poured mass by supplying heat generated outside the lingotforming chamber to the lower portion of the mold, and progressively retarding upwardly the soliditlcation of the upper portion of the poured mass radially opposite the upper portion of the metallic sidewalls of the chamber'by. circungferentially retarding the dissipation of heat rom the outer` peripheral metallic surface of the side walls of the mold in the upper portion radially opposite the ingot-forming chamber.

10. A method of casting ingots including pouring molten metal into a vertical metallic mold -provided with an ingot-forming chamber of upwardly tapering cross-section, absorbing heat basally, and cooling the poured mass along the side walls'of the mold at a radial rate suiilcient toproduce a skin on the poured mass of substantially uniform thickness to confine the molten interior, providing sliding contactnbetween the sidewalls of the mold and the skin ofp the forming-ingot by) moving the side walls of the mold longitudinally downwardly relatively to the poured mass and the base support of said poured mass, and progressively retarding upwardly the oudincation of the upperpcrtion of the poured u mass radiallyopposite the upper portion of the metallic side walls of the chamber by circumferentially retarding the dissipation of heat from the outer peripheral metallic surface of the side t 5 pering cross-section, the larger end of which is walls of thefmold in the upper portion radially opposite thei'ingot-formin'g chamber while retarding the cooling of the lower portion of the "ingot by supplying heat of relativelyl high temprature and generated outside the ingot-form- .lng chamber to the lower portion of the metallic mold and to the bottom of the metallic bottom- Aclosure of said ingot-forming chamber.

1l. A method of casting ingots including pouriligmoltenmetal intona.,yerticalmetallic mold provided with an ingot-'forming charnlie"r itv tas,s4o,4os y pering `cross-section, the larger end of which is down, absorbing 'heat basally, and cooling theA poured mass along the sidewalls of the mold at a radial rate suillcient to produce a skin on the s poured mass ofv substantially uniform thickness to conne the molten interior. thickening the skin by providing sliding contact between the sidewalls or the mold and the ingot skin by movingthe sidewalls or the mold @longitudinally downward l0 relatively to the ingot and the ingot base support,

and later partially stripping the ingot by moving the ingot longitudinally downwardly relatively to the side walls of the mold. f

l2. An ingot mold assembly including the com- 5 bination of a vertically extending metallic mold body provided with an ingot-forming, chamber of tapering cross-section, the larger end of which is d own, a separable metallic bottom-closure at said larger end of the ingot-forming chamber.'

and a mutable support disposed beneath said vertically extending mold body and supporting said mold body for downward longitudinal movement relatively to said bottom-closure.

1,3. An ingot mold assembly including the combination or a vertically extending metallic mold body -provided with an ingot-forming chamber vof tapering cross-section, the larger end of which is down, a separable metallic bottom-closure, a

mutable support supporting the vertical moldbody longitudinally movable relatively to said bottom-closure, and a removable body of relatively great weight superimposed-upon the puter peripheral side of the vertical mold body.

14, An ingot mold assembly including the com- 5 bination oi a vertically extendingimetallic mold body provided with an ingot-forming chamber oi tapering cross-section .the larger end of which is down. andi?l metallic stool carrying a metallic bottom-closure for the chamber, said mold body 40 being mutablysupported for downward longitudinal movement relatively to the o amber bot-- tom-closure, combustible materialcapabie of evolving great heat provided in the stool and' adapted to supply heat to the bottom of the bottom-closure, and means to torce air tothe combustible material.

l5. An ingot mold assembly includintnhe 'combination of a vertically extending me c mold body provided with an ingotforming chamber of tapering cross-section, the larger end o i whimsis down, said mold body being mutably supported for downward longitudinal movement relatively Vto a metallic chamber bottom-closure'carried by 'a stool, combustible material capable or evolving great heat provided in the stool and adapted to supply heat to the bottom or the bottom-closure.

vmeans to'convey air to saidcombustible x'naterialv to support combustion, and a removable bodyot l relatively great weight superimposed upon the outerperipheral side or the vertical mold body.

16.An ingot mold assembly including the com-y bination oi a vertically extending metallicmold body provided with an ingot-forming chamber ot down. a separable metallic bottom-closure at said larger end of the ingot-forming chamber, a mutable support disposed beneath said vertically extending mold body and-supporting said mold .m body for downward longitudinal movement rela- 1s sauleV on. and substantially symmetrically di mutably supporting the tion of said combustible tributed on. diametrically opposite sides ofKsaid mold body.

17. In casting apparatus, an ingot mold assembly including the combination cf a. vertically extending metallic mold body provided with an l inzet-forming chamber of tapering cross-section,

a, combustible support vertical mold body for movement relatively to adapted to supply heat vmetallic bottom-closure.

downward longitudinal said bottom-closure and bination of a vertically extending metallic mold body provided with an inset-(forming chamber oi.` tapering, cross-section,

is down, a separable metallic chamber-bottomto the lower portion of the moldduring diminuthe assembly to support means to supply air to and means to control combustible bustlon.

18. Ingot casting apparatus including the combination oi' a vertically extending metallic mold body provided with an ingot-forming chamber of tapering cross-section, the larger end of which is down, a metallic stool provided with arigidly supported plug-like bottom-closure at the larger a continuous channel in the the combustible support. the combustible support, the supply of air to said support for varying its rate of comend of the hamber,

stool surrounding the bottom-closurel and adapt# ed to receive the lower marginal end wall of said vertical mold body, a combustible support in the control and vary the combustible material.

19. Ingotfcasting apparatus including the combination of support, rigid means in v l said bottom-closure and v tending metallic mold closure, means mutably supporting the vertical mold body for downward longitudinal movement relatively to said chamber-bottom-closure. and

a sleeve-like conservator of heat adjustably supported relatively to and surrounding the upper portion of the outer periphery of the vertical mold rial on its inner peripheral wall.

21. In casting apparatus, an ingot mold assembly including the combination of a'vertically exdownward longitudinal movement relatively to 'adapted to supply heat tothe lower portion of the mold during diminution 'of said combustible support, rigid means in the assembly to support the combustible support,

metallic bottom-closure, a1 combustible-'support to the lower portion of the moldluring tion of saidA combustible support, rigid vmeans the' assembly to support said combustible sup means to supply air to said combustiblel posed upon said vertical mold body, and a .sleeve like conservator of Y'relatively to and surrounding the upper portion of the outer and includin tlie larger end of which varying 'its rate of combus.

an lngot mold assem- I provided with an intlallyl prevent, axial ber-bottom-closure, and means said mutable means supporting said chamber-l '10i thexvertical mold body to prevent, or to substantiltinggof said vertical mold body.. 4

24. An ingot mold assembly including the combination oi a vertically extending metallic mold body provided with an ingot-iorming chamber or upwardly able metallic'vchamber-bottom-ciosure, lmutable means, supporting said mold bodyfor downward4 longitudinal movement relatively 'to saidgcham-f independent'. of

bottom-closure for downward longitudinal movement relativelytosaid moldbody.

25. An ingot mold assembly including the combination of a vertically extending metallic ing'ot-forming chamcross-section, a metallic stool provided with a plug-like bottom-closure at the larger end of ber of tapering tapering cross-section, a sepan-v t material, means to control the supply of air to.

the larger end of the chamber. a continuousl channel in the stool surrounding the bottom-closure and adapted to receive the lower marginal end wall oi said vertical mold body, amutable support in the channel mutably supporting thegzvertical mold body longitudinally movable downwardly relatively to the plug-like bottom-closure, and movable rigid means supporting said plug-like bottom closure for downward longitudinal movement relatively tothe vertical moldbody. Y

26.. Casting apparatus including in combination, a vertically extending metallic mold body provided with an ingot-Iorming chamber of tapering cross-section, the larger end of which is down, a metallic stool provided' with a pluglike bottom-closure at the -larger end of the chamber, a continuous channel in the stool surrounding the bottom-closure and adapted to receive the lowermarginal end wall of said vertical mold body, a combustible support in the channel mutably supporting the vertical mold body for downward longitudinal movement relatively to the plug-like the' outer peripheral side of the vertical mold body at the bottom marginal end thereof cooperable with `means on the outer side wall of the channel inthe stool for guiding the downward movement of the vertical mold body to prevent, or substantially prevent, axial tilting of said vertical mold body, movable rigid means supporting ithe plug-like bottom-closure for downward longitudinal movement relatively to the vertical mold body, a recess in the stool inrmediately below the bottom-closure, combustible material capable of evolving great heat provided in said recess and adapted during combustion to supply heat to the bottom of said bottom-elo.-

bottom-closure, 'means on sure, means to supply air to the combustible support, means to supply air to said combustible said combustible support and said combustible material for varying their ratesy of combustion, and a sleeve-like conservator of heat adjustably supported vrelatively to and surrounding the upper portion of the outer periphery of the vertical mold body and including a compressible elastic facing oi heat-insulating material on its inner peripheral wall.

27. Casting apparatus including in combination, a vertically extending metallic mold body provided with an ingot-forming chamber of tapering cross-scetion, the larger end of which is down, a metallic stool provided 'with a pluglike bottom-closure at the larger end oil the chamber, a continuous channel in the stool surrounding said bottom-closure and adapted to receive the lower marginal end wall of said vertical mold body, a combustible support in'said channel mutably supporting said vertical mold body for downward longitudinal movement relatively to said plug-like bottom-closure, means on the outer peripheral side of said vertically extending mold body at thevbottom marginal end thereof cooperable with neans on the outer side wall oi said channel in said stool for guiding downward movement ot said mold body tov prevent, or substantially prevent, axial tilting of said mold body, a removable body of relatively great weight superimposed upon the outer peripheral side of said mold body and having the weight of its mass the same on, and symmetrically distributed on, diametrically opposite sides of said mold body, movable rigid means supporting said plug-like bottom-closure for downward longitu- `dinal movement relatively to said mold body, a recess in said stool immediately below said bottomclosure,- combustible material capable of evolving great heat provided in said recess and adapted during combustion to supply heat to the bottom ofv said bottom-closure, means to supply air to said combustible support, means to supply air to said-combustible material, 1means to controlthe supply of air to said combustible support and to said combustible material for varyt 

